The present invention relates to a polar (or polarized) relay, and more particularly to a polar relay of a balanced-armature type. Also, the present invention relates to an information processing apparatus provided with a balanced-armature type polar (or polarized) relay. The present invention further relates to a method of manufacturing a balanced-armature type polar relay.
A polar relay that is comprised of a base, an electromagnet incorporated into the base, a permanent magnet provided in conjunction with the electromagnet, an armature supported pivotably on the base, the armature having a pair of abutting surfaces in opposite end regions at a distance from the pivoting center of the armature, which are opposed to and capable of abutting on a pair of core polar surfaces of the electromagnet, at least one electrically conductive plate spring pivotable on the base along with the armature, movable contacts provided on the opposite ends of each of at least one conductive plate spring, and a plurality of fixed contacts disposed securely on the base so as to be respectively opposed to and capable of coming into contact with the corresponding movable contacts, is known as a balanced-armature type polar relay. Generally, this type of polar relay has advantages of higher sensitivity, shorter operating time, etc., in comparison with a non-polarized relay, as well as being easy to reduce in size and power consumption, so that, in recent years, they have been increasingly utilized in various information processing apparatuses, such as modems and facsimiles in offices and homes, which are adapted to be connected to telecommunications channels or electric communication lines.
When telecommunications-channel connectable equipment are to be connected to a telecommunications channel (e.g., a telephone circuit), it is required that circuits (a power circuit, a signal circuit) of the connectable equipment are isolated from the telecommunications channel with sufficient dimensions for insulation (i.e., sufficient insulation distances), as prescribed, for respective utilized voltages, in the international standard IEC60950. Conventionally, in order to assure such insulation distances as prescribed, certain measures have been taken, wherein a non-polarized relay having a relatively large open- or break-contact distance (that is, a maximum distance between contacts during the travel of an armature) is adopted as a relay to be mounted in the telecommunications-channel connectable equipment, or wherein a transformer is interposed between the circuit of the connectable equipment and the telecommunications channel.
The above described conventional measures for insulation meeting the requirements of IEC60950 have some problems to be solved, from the viewpoint of reduction in size and in power consumption. First, in the case of mounting a non-polarized relay in the connectable equipment, the non-polarized relay has a long armature travel and thus the finished product has relatively large external dimensions, which may become factors inhibiting the reduction in size and power consumption of the connectable equipment. On the other hand, when a low power-consumption polar relay, as described above, is mounted in the telecommunications-channel connectable equipment, the polar relay has, in general, a relatively small open- or break-contact distance, which would require the provision of a transformer, mounted in the connectable equipment, to be interposed between a circuit of the connectable equipment and the telecommunications channel, so as to meet the requirements of IEC60950. Thus, in this case, even when a sufficiently small polar relay is used, the existence of the transformer may resultingly hamper the size reduction of the telecommunications-channel connectable equipment.
Further, in order to meet the requirements of IEC60950, it is desired for a relay to be mounted in telecommunications-channel connectable equipment such that sufficient insulation distances are assured not only between contacts in an opened state but also between, for example, a contact and a coil of an electromagnet, or between contacts arranged side-by-side in the case of a double-circuit type relay. Especially, in a miniature polar relay, it has been a problem to assure the insulation distances between various above-described components.
It is an object of the present invention to provide a polar relay, of a balanced-armature type, that is capable of assuring, by its own structure, sufficient insulation distances, meeting the requirements of IEC60950, when it is mounted in telecommunications-channel connectable equipment.
It is another object of the present invention to provide a polar relay, of a balanced-armature type, that is capable of increasing insulation distances required between contacts in an opened state, while the external dimensions of the finished product are prevented from increasing as effectively as possible.
It is still another object of the present invention to provide a polar relay, of a balanced-armature type, that is capable of assuring sufficient insulation distances required between a contact and a coil, while the external dimensions of the finished product are prevented from increasing as effectively as possible.
It is still another object of the present invention to provide a polar relay, of a balanced-armature type, that is capable of assuring sufficient insulation distances required between contacts arranged side-byside, while the external dimensions of the finished product are prevented from increasing as effectively as possible.
It is still another object of the present invention to provide a miniature information processing apparatus, of a low power-consumption type, that is capable of assuring sufficient insulation distances meeting the requirements of IEC60950, when it is connected to a telecommunications channel.
It is still another object of the present invention to provide a method for manufacturing a polar relay that 15 is capable of assuring, by its own structure, sufficient insulation distances, meeting the requirements of IEC60950, when it is mounted in telecommunications-channel connectable equipment.
In order to accomplish the above objects, the present invention provides a polar relay comprising a base; an electromagnet incorporated into the base; a permanent magnet provided in conjunction with the electromagnet; an armature pivotably supported on the base and having a pair of abutting surfaces disposed in opposite end regions at a distance from a pivoting center, which are respectively opposed to and capable of abutting on a pair of core polar surfaces of the electromagnet; at least one electrical conductive plate spring pivotable on the base along with the armature; a plurality of movable contacts provided on opposite ends of each of the at least one electrical conductive plate spring; and a plurality of fixed contacts arranged securely on the base, the fixed contacts being respectively opposed to and capable of coming into contact with the movable contacts; wherein the maximum distance between one of the movable contacts and one of the fixed contacts, capable of coming into contact with each other during the travel of the armature, is set to 1 mm or more.
In the preferred aspect, the polar relay is constituted such that at least one of each of the pair of abutting surfaces of the armature and each of the pair of core polar surfaces of the electromagnet, opposed to the abutting surface, is formed as an inclined surface for reducing an angle between opposed surfaces, during a mutual abutment, as much as possible, and that the armature passes, during the travel thereof, a position where each of the pair of abutting surfaces oppositely faces a corresponding one of the pair of core polar surfaces in parallel with each other.
In this arrangement, the thickness of the opposite end regions in a pivoting direction of the armature may gradually decrease toward opposite ends of the armature, the pair of abutting surfaces being thereby formed as the inclined surfaces.
In this case, it is advantageous that a non-magnetic layer is formed on one of the abutting surfaces of the armature which is arranged on a make side.
It is also preferred that the thickness of the non-magnetic layer is uniform.
The permanent magnet may be fixedly connected to the armature in a position deviated toward a break side.
In another preferred aspect, comprising at least two electrically conductive plate springs, the polar relay further comprises an insulating member integrally connecting the armature with the at least two electrically conductive plate springs so as to be spaced in a lateral direction perpendicular to a pivoting direction of the armature and arranged side-by-side while at least the abutting surfaces and the movable contacts are exposed, wherein the insulating member covers most of an intermediate portion of the armature located between the opposite end regions, and wherein the at least two electrically conductive plate springs are disposed so as to define, at proximal end portions thereof projecting from the insulating member, a lateral distance from the insulating member, smaller than a lateral distance between the movable contacts and the abutting surfaces.
In this arrangement, the polar relay may be provided, wherein the thickness of the opposite end regions in the pivoting direction of the armature gradually decreases toward opposite ends of the armature, and wherein a dimension of the opposite end regions in a lateral direction of the armature, perpendicular to the pivoting direction, is larger than a dimension of the intermediate region in the lateral direction.
In a further preferred aspect, the polar relay is provided wherein the electromagnet includes a core, an insulating bobbin attached to the core with the pair of core polar surfaces exposed, and a coil wound on the insulating bobbin, wherein the base includes an insulating upper plate interposed between the armature and the coil and cooperating with the insulating bobbin to increase dimensions for insulation, required between the pair of core polar surfaces and the coil, and wherein the insulating bobbin and the insulating upper plate are provided with combined portions to be complementarily combined with each other at a location between the pair of core polar surfaces and the coil.
In this arrangement, it is advantageous that the core includes, near the pair of core polar surfaces, overhang portions projecting from a surface of the insulating bobbin, and that the insulating bobbin covers the core except for the pair of core polar surfaces as well as regions including the overhang portions and surrounding the core polar surfaces.
Also, the base may include an insulating bottom plate cooperating with the insulating upper plate to increase dimensions for insulation, required between a plurality of terminals respectively having the fixed contacts thereon and the coil, and the insulating upper plate and the insulating bottom plate may be complementarily combined with each other at a location between the terminals and the coil.
In this case, it is preferred that a sealant is applied to the complementarily combined portions of the insulating upper plate and the insulating bottom plate for sealing any gap between the combined portions.
In a further preferred aspect, the polar relay includes an insulating surface zone provided between the pair of core polar surfaces of the electromagnet and the plurality of fixed contacts so as not to expose the surfaces to each of the fixed contacts.
The polar relay according to the present invention is effectively usable, especially, for assuring dimensions for insulation, required between circuits as prescribed in IEC60950 regarding an information processing apparatus connectable to a telecommunications channel.
The present invention further provides an information processing apparatus connectable to a telecommunications channel, wherein a polar relay, as described above, is arranged between an inner circuit of the information processing apparatus and a telecommunications channel to assure dimensions for insulation, required between circuits.
The present invention further provides a method for manufacturing a polar relay, as described above, comprising providing a magnetic plate including a flat first surface, and a second surface having a major flat-face portion parallel to the first surface and an inclined-face portion crossing at an obtuse angle with the major flat-face portion and extending in a direction approaching the first surface; forming a non-magnetic layer having a uniform thickness on the first surface of the magnetic plate in a region located opposite to the inclined-face portion; opposing the second surface of the magnetic plate to a flat supporting plane, and securely placing the magnetic plate on the supporting plane; pressing a region of the first surface including the non-magnetic layer, to deform the magnetic plate while maintaining the uniform thickness of the non-magnetic layer until a surface of the non-magnetic layer exhibits a mirror image shape of the inclined-face portion provided in the second surface and the inclined-face portion shifts to a plane common to the major flat-face portion; and forming, from the magnetic plate, the armature including a region of the non-magnetic layer arranged on either one of the pair of abutting surfaces.